The acrylic rubber-metal composite, which comprises a metal and an acrylic rubber as vulcanization bonded to each other, has been so far used to produce oil-resistant and heat-resistant parts, for example, oil seals. Such parts have been sometimes exposed to contamination of service oil with water, depending on service locations, and thus a water resistance has now been further indispensable in addition to the afore-mentioned characteristics.
In the vulcanization bonding of a metal and an acrylic rubber, processes for coating to surface-treated metals, for example, as surface-treated by a chemical treatment such as zinc phosphate treatment, etc., a blast treatment, or a primer treatment, with a phenol resin-based adhesive are usually used to enhance chemical and physical bonding forces. However, it is difficult to apply such surface treatments to surface roughness-requiring positions. Furthermore, the surface treatment is a prerequisite processwise for the bonding treatment, resulting in an increase in process steps. Thus, it is preferable to bond a metal to an acrylic rubber without application of the surface treatment.    Patent Literature 1: JP-A-10-121020    Patent Literature 2: JP-A-11-001672    Patent Literature 3: JP-A-11-061053    Patent Literature 4: JP-A-2000-017247
Direct application of so far used ordinary phenol resin-based adhesives to metals without surface treatment, for example, a chemical treatment such as zinc phosphate treatment, etc., a blast treatment, or a primer treatment, still now suffers from such problems as low tight-adhesion to metals and hard attainment of even an initial adhesiveness.